This example activates member servers in the DAG DAG1 for the Active Directory site Portland. In this example, the values for the AlternateWitnessServer parameter and the AlternateWitnessDirectory parameter had been previously set by using the Set-DatabaseAvailabilityGroup cmdlet. Thus, there is no need to specify them here.

This example activates member servers in the DAG DAG1 for the Active Directory site Redmond. In this example, the values for the AlternateWitnessServer parameter and the AlternateWitnessDirectory parameter are being set as part of the activation process.

You can also use this cmdlet for disaster recovery purposes to restore functionality to a DAG that has lost quorum due to one or more DAG members being offline for an extended period. Before running this cmdlet, you must first run the Stop-DatabaseAvailabilityGroup cmdlet.

The Restore-DatabaseAvailabilityGroup cmdlet can be run against a DAG only when the DAG is configured with a DatacenterActivationMode parameter value of DagOnly. For more information about the DatacenterActivationMode parameter, see Datacenter Activation Coordination mode.

You can use the Set-DatabaseAvailabilityGroup cmdlet to configure the value for the DatacenterActivationMode parameter.

The Restore-DatabaseAvailabilityGroup cmdlet performs several operations that affect the structure and membership of the DAG's cluster. This task does the following:

Forcibly evicts the servers listed on the StoppedMailboxServers list from the DAG's cluster, thereby reestablishing quorum for the cluster enabling the surviving DAG members to start and provide service.

Configures the DAG to use the alternate witness server if there is an even number of surviving DAG members, or a single surviving DAG member.

You need to be assigned permissions before you can run this cmdlet. Although all parameters for this cmdlet are listed in this topic, you may not have access to some parameters if they're not included in the permissions assigned to you. To see what permissions you need, see the "Database availability groups" entry in the High availability and site resilience permissions topic.

The Identity parameter specifies the name of the DAG being manipulated.

ActiveDirectorySite

Optional

Microsoft.Exchange.Configuration.Tasks.AdSiteIdParameter

The ActiveDirectorySite parameter specifies the site containing the DAG members to be restored.

AlternateWitnessDirectory

Optional

Microsoft.Exchange.Data.NonRootLocalLongFullPath

The AlternateWitnessDirectory parameter specifies the name of an alternate directory used to store witness data. The specified directory must not be in use by any other DAGs or used for any other purpose. This value can be populated ahead by using the Set-DatabaseAvailabilityGroup cmdlet.

AlternateWitnessServer

Optional

Microsoft.Exchange.Data.FileShareWitnessServerName

The AlternateWitnessServer parameter specifies the name of a new witness server for the DAG as part of a site activation process. This value can be populated ahead by using the Set-DatabaseAvailabilityGroup cmdlet.

Confirm

Optional

System.Management.Automation.SwitchParameter

The Confirm switch specifies whether to show or hide the confirmation prompt. How this switch affects the cmdlet depends on if the cmdlet requires confirmation before proceeding.

Destructive cmdlets (for example, Remove-* cmdlets) have a built-in pause that forces you to acknowledge the command before proceeding. For these cmdlets, you can skip the confirmation prompt by using this exact syntax: -Confirm:$false.

Most other cmdlets (for example, New-* and Set-* cmdlets) don't have a built-in pause. For these cmdlets, specifying the Confirm switch without a value introduces a pause that forces you acknowledge the command before proceeding.

DomainController

Optional

Microsoft.Exchange.Data.Fqdn

The DomainController parameter specifies the domain controller that's used by this cmdlet to read data from or write data to Active Directory. You identify the domain controller by its fully qualified domain name (FQDN). For example, dc01.contoso.com.

UsePrimaryWitnessServer

Optional

System.Management.Automation.SwitchParameter

The UsePrimaryWitnessServer parameter specifies that the DAG's currently configured witness server should be used if a witness is needed by the DAG members being activated.

WhatIf

Optional

System.Management.Automation.SwitchParameter

The WhatIf switch simulates the actions of the command. You can use this switch to view the changes that would occur without actually applying those changes. You don't need to specify a value with this switch.